Zeitschriftenartikel: „Deflecting Structure“

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Quan, Hui, Yongkang Wu, Ying Guo, Kai Song und Yanan Li. „Multiobjective Hydraulic Design and Performance Analysis of a Vortex Pump Based on Orthogonal Tests“. Shock and Vibration 2021 (29.03.2021): 1–14. http://dx.doi.org/10.1155/2021/6687856.

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We design optimization on the overall blade structure of a vortex pump conducted by using the orthogonal test method to clarify the matching relationship of impeller and casing structures and then improve the hydraulic performance of the vortex pump. Based on two different impeller structures of forward-deflecting (denoted as R1 − F2) and backward-deflecting (denoted as F1 − R2), key parameters describing the impeller structure are calculated through optimization for the objective function of hydraulic efficiency by means of orthogonal tests and computational fluid dynamic simulations. Optimization computations show that the forward-deflecting blade impeller is superior to the backward-deflecting one. Model test of the optimized vortex pump is carried out calculating the error from the comparison of pump efficiencies calculated by model test and numerical simulation is calculated to be less than 6%. The experimental verification shows that the flow simulation has some errors. The weight of structure parameters such as the blade installation angle (α), the blade deflecting angle (β), the position of blade deflecting point (L), the radius (r) of smoothing arc at the deflecting point, the wedge type (W) of blade, to the lift head, the flow rate, and the efficiency of the pump is investigated, through multiparameter optimizations. Visualization observation of flows in the model pump consisted of a back-placed impeller and a front vaneless chamber is further performed. The characteristic of vortex formation predicted by flow simulation agrees with the result of visualization observation. The above results demonstrate that the optimum impeller type of vortex pump is forward-deflecting blade impeller. The optimum combination of the key structure parameters is that the deflection angle of the blade inlet (α) equals 30°, the position of blade deflecting point lM = 2/3 L, the chamfering radius (r) at the deflecting point r = 3 mm, and the best wedge type is axial deflecting blade.

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Volobuev, E. N., A. A. Zavadtsev, D. A. Zavadtsev, L. V. Kravchuk, V. V. Paramonov, M. V. Lalayan, A. J. Smirnov, N. P. Sobenin und D. V. Churanov. „Transverse deflecting structure XFEL TDS INJ“. Journal of Physics: Conference Series 747 (September 2016): 012083. http://dx.doi.org/10.1088/1742-6596/747/1/012083.

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3

Shi, Shao Yan, Yi Jiang und Xiao Tong Dong. „Deflecting Features of Gas from Double-Faced Deflector and Structure Optimization of Deflector“. Applied Mechanics and Materials 387 (August 2013): 314–18. http://dx.doi.org/10.4028/www.scientific.net/amm.387.314.

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This paper uses three-dimensional dynamical simulation of gas jet to demonstrate basic deflecting features of the double-faced deflector, during the launch process of the land-based missile with the vehicle-mounted vertically thermal launch. The calculation shows that the deflection of the gas flow is good, reducing knock-on effect and ablative effect on launch device. But wheels of the launch vehicle are still under visible influent from the gas flow. The paper optimizes the double-faced deflector and compares different suggestions in order to find a better deflection.

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Bolgov, R. O., M. A. Gusarova, D. S. Kamenshchikov, M. V. Lalayan, A. Yu Smirnov und N. P. Sobenin. „Higher order modes in an RF deflecting structure“. Instruments and Experimental Techniques 54, Nr. 6 (November 2011): 813–22. http://dx.doi.org/10.1134/s0020441211060030.

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5

Staras, S. „Simulation and properties of the twined helical deflecting structure“. IEEE Transactions on Electron Devices 49, Nr. 10 (Oktober 2002): 1826–30. http://dx.doi.org/10.1109/ted.2002.803643.

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Piekarczyk, Adam. „Reinforced and unreinforced AAC masonry walls supported on deflecting structure“. ce/papers 2, Nr. 4 (September 2018): 377–87. http://dx.doi.org/10.1002/cepa.861.

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Jia, Ya Lei, Zhong He Han, Fu You Li, Ya Kai Bai und Ji Xuan Wang. „Influence of Flap Deflection Angle on Wind Turbine Airfoil with Trailing Edge Flaps“. Advanced Materials Research 977 (Juni 2014): 222–27. http://dx.doi.org/10.4028/www.scientific.net/amr.977.222.

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To improve the ability of capturing the wind energy of wind turbine and shorten the design period is of great importance to designing wind turbine blade. The article established S809 airfoil model with trailing edge flaps, The gap of the frontal subject and trailing edge flap adopt uniform gap structure, this structure will reduce the influence of the gap on aerodynamic characteristics.Using the k-ω Two equation turbulence model , the article calculated aerodynamic performance of S809 with 10% chord length trailing edge flaps under different deflecting angles. Results show that gap between the main body and trailing edge flap has little effect on airfoil aerodynamic performance, however, the deflection Angle of Trailing edge flap have great affect on airfoil aerodynamic performance, when deflection Angle of trailing edge flap is 14 ° degrees ,the lift-to-drag ratio is the largest.

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Volobuev, E. N., A. A. Zavadtsev, D. A. Zavadtsev, A. J. Smirnov, N. P. Sobenin und D. V. Churanov. „High power RF system for transverse deflecting structure XFEL TDS INJ“. Journal of Physics: Conference Series 747 (September 2016): 012081. http://dx.doi.org/10.1088/1742-6596/747/1/012081.

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Jing-Ru, Zhang, Hou Mi, Dai Jian-Ping, Pei Shi-Lun und Pei Guo-Xi. „Design and studies on the traveling wave transverse RF deflecting structure“. Chinese Physics C 32, Nr. 3 (März 2008): 232–35. http://dx.doi.org/10.1088/1674-1137/32/3/015.

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10

Piekarczyk, Adam. „The experimental investigation of the failure of load-bearing masonry walls supported by a deflecting structure“. Budownictwo i Architektura 19, Nr. 3 (30.09.2020): 127–41. http://dx.doi.org/10.35784/bud-arch.2142.

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The paper presents selected results of tests of full-scale masonry walls linearly supported on a deflecting beam. The walls with thin bed joints and unfilled head joints were 4.55 m long and 2.45 m high, and were made of group 1 calcium silicate masonry units. The tests included walls with and without openings. The tests were carried out in a specially designated and constructed test stand, which allowed simultaneous vertical load on the upper edge of the wall and vertical deflection of the beam supporting this wall. During the test, measurements of mutual displacements of six points on the wall surface were carried out. On both faces of masonry specimens, the changes of the length of the measuring bases connecting these six points were recorded. Walls without openings were detached from the central part of the supporting beam at a deflection not exceeding 2 mm. Walls with one door opening also cracked at an early stage of tests. In this case, a detachment from the supporting beam and cracking at the ends of the lintel occurred because of the rotation of the pillars connected by the lintel above the opening. In walls with two door openings, first cracks were formed at the ends of lintels due to the rotation of pillars with a small deflection of the supporting beam, less than 3 mm. Whereas, in walls with door and window openings, first cracks occurred under the window and at the end of the lintel in the outer pillar of the wall.

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Elsafti, Hisham, Hocine Oumeraci und Hans Scheel. „HYDRODYNAMIC EFFICIENCY AND LOADING OF A TSUNAMI-FLOODING BARRIER (TFB)“. Coastal Engineering Proceedings, Nr. 35 (23.06.2017): 23. http://dx.doi.org/10.9753/icce.v35.structures.23.

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The Tsunami-Flooding Barrier (TFB) is an impermeable vertical structure proposed at relatively large water depths, at which it is theorised that a tsunami will reach the structure before turning into a bore. The proposed hypothesis is tested in this study by means of a validated Computational Fluid Dynamics (CFD) model. The hydrodynamic efficiency of the impermeable TFB structure is confirmed and the effect of different aspects on the hydrodynamic efficiency of the structure are studied. These aspects include water depth, free board, surface roughness and the consideration of a deflecting parapet (named here as a surge stopper). Further, a new method is developed for calculating the tsunami-like solitary wave run-up and loads on the structure. The method is then compared to the Goda method for calculating storm wave loads on vertical impermeable structures. It is concluded that using the Goda method will severely underestimate the tsunami-like solitary wave load on the TFB structure.

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Mahzan, Muhammad Iyas, Sallehuddin Muhamad, Sa’ardin Abdul Aziz und Mohamed Sukri Mat Ali. „Composite Wing Flutter Speed and Frequency due to Variable Control Surface Deflection in Low Speed Wind Tunnel“. Applied Mechanics and Materials 390 (August 2013): 3–7. http://dx.doi.org/10.4028/www.scientific.net/amm.390.3.

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Flutter is a dynamic instability problem represents the interaction among structural, aerodynamic, elastic and inertial forces and occurred when the energy is continuously transformed by the surrounding fluids to a flying structure in the form of kinetic energy. The study was conducted to investigate the relationship of the control surface deflection angle to the flutter speed and the flutter frequency. A wind tunnel test was performed using a flat plate wing made of composite material. It was found that by deflecting the control surface up to 45°, the flutter speed reduced almost linearly from 35.6 m/s to 22.7 m/s. The flutter frequency greatly reduced from 48 Hz without the control surface deflected to 34 Hz with the control surface deflected at 15°. After 15° deflection up to 45°, the flutter frequency reduced almost linearly.

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Ego, H., H. Maesaka, T. Sakurai, Y. Otake, T. Hashirano und S. Miura. „Transverse C-band deflecting structure for longitudinal electron-bunch-diagnosis in XFEL “SACLA”“. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 795 (September 2015): 381–88. http://dx.doi.org/10.1016/j.nima.2015.06.018.

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Mobki, Hamed, Kaveh Rashvand, Saeid Afrang, Morteza H. Sadeghi und Ghader Rezazadeh. „DESIGN, SIMULATION AND BIFURCATION ANALYSIS OF A NOVEL MICROMACHINED TUNABLE CAPACITOR WITH EXTENDED TUNABILITY“. Transactions of the Canadian Society for Mechanical Engineering 38, Nr. 1 (März 2014): 15–29. http://dx.doi.org/10.1139/tcsme-2014-0002.

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In this paper, a novel RF MEMS variable capacitor has been presented. The applied techniques for increasing the tunability of the capacitor are the increasing of the maximum capacitance and decreasing of the minimum capacitance. The proposed structure is a simple cantilever Euler–Bernoulli micro-beam suspended between two conductive plates, in which the lower plate is considered as stationary reference electrode. In this structure, two pedestals are located in both tips of the cantilever beam. In the capacitive micro-structures, increasing the applied voltage decreases the equivalent stiffness of the structure and leads the system to an unstable condition (pull-in phenomenon). By deflecting the beam toward the upper (lower) plate the minimum (maximum) capacitance decreases (increases) and tunability increases consequently. The located pedestals increase and decrease the maximum and minimum capacitance respectively. The results show that the proposed structure increases the tunability of cantilever beam significantly. Furthermore, bifurcation behavior of movable electrode has been investigated.

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YOSHIDA, Fumiya, Taichi USUZAWA und Takahiro KIWATA. „S0510402 LES of a Flow Structure for Round Jet with Divergent and Convergent Deflecting Ring“. Proceedings of Mechanical Engineering Congress, Japan 2014 (2014): _S0510402——_S0510402—. http://dx.doi.org/10.1299/jsmemecj.2014._s0510402-.

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Marx, D., R. Assmann, U. Dorda, B. Marchetti und F. Mayet. „Lattice considerations for the use of an X-band transverse deflecting structure (TDS) at SINBAD, DESY“. Journal of Physics: Conference Series 874 (Juli 2017): 012078. http://dx.doi.org/10.1088/1742-6596/874/1/012078.

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Damghanian, Mitra, und Burhanuddin Yeop Majlis. „Novel Design and Fabrication of High Sensitivity MEMS Capacitive Sensor Array for Fingerprint Imaging“. Advanced Materials Research 74 (Juni 2009): 239–42. http://dx.doi.org/10.4028/www.scientific.net/amr.74.239.

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A novel MEMS capacitive pressure sensor array is designed and fabricated for fingerprint acquisition application. Based on analytical investigations and FEM analysis, the designed structure of pressure sensor cells assist from an aluminum clamped-clamped wide beam as the movable electrode of variant capacitor, instead of usual membrane structure. A rectangular base T-shape protrusion is also used on top of the deflecting electrode to concentrate pressure and increase the sensitivity. Proven by the real test of the fabricated sensor structure, this design has enhanced sensitivity and linearity of the device compared to all membrane based reported prototypes without crossing the dpi limits. Structural modifications have resulted in a simpler fabrication process as well.

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Sun, Xiang, Zong Zhi Yang, Yun Gang Liu, Mai Quan Zhang und Yuan Fei Zhu. „Structure Dynamic Response Analysis of Pipe String under the Action of Perforating Detonation Wave“. Advanced Materials Research 986-987 (Juli 2014): 887–90. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.887.

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Impact load of perforation will result in strong vibration of downhole string, string operated such as bending fracture accidents. Considering the clearance between string and casing, using space beam and spring element to solve the nonlinear contact problems between oil jacket, established the numerical model of string structure dynamic response analysis in horizontal well. Extracting downhole perforation pressure wave monitoring data, using the finite element software ANSYS, analyzed the dynamic response of the tubing under perforation of detonation shock wave impact, got the displacement of the tubing、acceleration time history. The results show that, without packer, the maximum Mises equivalent stress in the end of the string, the deformation and stress changes in deflecting section of the tubing string are bigger than in vertical Wells.

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Djoković, Jelena M., Ružica R. Nikolić, Ján Bujňák und Branislav Hadzima. „Criteria for Prediction the Interfacial Crack Growth in Concrete“. Solid State Phenomena 258 (Dezember 2016): 514–17. http://dx.doi.org/10.4028/www.scientific.net/ssp.258.514.

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To understand the mechanical behavior of the concrete structures, one must analyze deformation and fracture of the interfaces between the constituents of the material that the structure is made of. Criteria for predicting the crack growth along an interface, based on the linear elastic fracture mechanics concept, applied for the cement substrate/aggregate interface, are presented in this paper. The two possible directions of the interfacial crack growth – the crack propagation along the interface and the crack kinking away from the interface are considered, with the corresponding energy release rates. For the case of the crack approaching the interface from one of the materials – cement, the competition between the crack deflecting into the interface and the crack penetrating the interface is considered with the corresponding energy release rates.

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Barazandeh, Farshad, Hossein Rahnamafard, Mehdi Rajabizadeh und Hossein Faraji. „Engineering observation of lateral undulation in colubrid snakes for wheel-less locomotion“. Robotica 30, Nr. 7 (14.12.2011): 1079–93. http://dx.doi.org/10.1017/s0263574711001251.

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SUMMARYNature has always inspired engineers. This research tries to understand the contribution of snake anatomy in its locomotion from engineering point of view to be adopted in the design of snake robots. Rib design and muscular structure of snake robots will have a great impact on snake robot flexibility, weight, and actuators' torque. It will help to eliminate wheels in snake robots during serpentine locomotion. The result of this research shows that snakes can establish the required peg points on smooth surfaces by deflecting the body and ribs. The results are verified by both field observations and simulation.

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Nunes, D., A. P. Gonçalves, J. Th M. De Hosson und P. A. Carvalho. „On the YFe11Mo intermetallic characterization“. Microscopy and Microanalysis 19, S4 (August 2013): 135–36. http://dx.doi.org/10.1017/s1431927613001293.

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Rare-earth intermetallic compounds adopting the tetragonal ThMn12–type structure and containing high Fe concentrations have attracted considerable attention in the field of permanent magnets. Among them, the Y-Fe-Mo series has been extensively investigated, especially by X-ray diffraction (XRD), but the microstructural characterization was very limited.In the present work, Y:11Fe:Mo has been prepared by melting Y, Fe and Mo in an arc furnace followed by splat-quenching and/or annealing treatments. The structure, chemistry and magnetic domain configurations of the resulting polycrystalline aggregates have been investigated by XRD, scanning and transmission electron microscopies (SEM and TEM, respectively), energy dispersive X-ray spectroscopy (EDS) and Lorentz microscopy.A special emphasis was given to Lorentz microscopy, where contrast is based on the Lorentz deflection imposed on electrons by the passage through a magnetic specimen. The magnetic domains have been imaged by the intermediate lens in Fresnel mode, with the objective lens switched off. In these conditions the intermediate lens is defocused so that out-of-focus images of the specimen are formed: the magnetic domain walls are imaged as alternate bright (convergent) and dark (divergent) lines. For the overfocused image, bright lines occur at the position of domain walls for which the magnetisation on either side is deflecting the electrons towards the wall, whereas dark lines are observed at the walls for which the magnetisation on either side is deflecting the electrons away from the wall. The opposite contrast is observed at the underfocused image.The results have shown that the tetragonal YFe11-xMoy phase is predominant, with a cellular dendritic morphology (Figure 1), but a considerable presence of -Fe(Mo) could be inferred, forming a coarse intercellular eutectic mixture. Significant Fe segregation occurred during annealing. However, this composition variation corresponded to an extremely limited evolution of the lattice parameters, the Rietveld analysis pointing to Fe vacancies at the 8i sites on the annealed material. XRD and EDS results indicate that the fraction of point defects in the ThMn12-type structure adapts to the processing route and that the stable configuration depends on the temperature. The current study also showed that grain boundaries are usually associated with domain walls and that YFe11Mo grains present internal domain walls forming stripe/maze patterns characteristic of high anisotropy materials (Figure 2), while residual -Fe(Mo) grains exhibit vortex configurations (see arrows in Figures 2 (a-c)).The work was supported by the Portuguese Science Foundation through the CTM/48617/2002 and PEst-OE/CTM-UI0084/2011 grants.

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Pan, B., J. Waguespack, M. E. Schnee, C. LeBlanc und A. J. Ricci. „Permeation properties of the hair cell mechanotransducer channel provide insight into its molecular structure“. Journal of Neurophysiology 107, Nr. 9 (01.05.2012): 2408–20. http://dx.doi.org/10.1152/jn.01178.2011.

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Mechanoelectric transducer (MET) channels, located near stereocilia tips, are opened by deflecting the hair bundle of sensory hair cells. Defects in this process result in deafness. Despite this critical function, the molecular identity of MET channels remains a mystery. Inherent channel properties, particularly those associated with permeation, provide the backbone for the molecular identification of ion channels. Here, a novel channel rectification mechanism is identified, resulting in a reduced pore size at positive potentials. The apparent difference in pore dimensions results from Ca2+ binding within the pore, occluding permeation. Driving force for permeation at hyperpolarized potentials is increased because Ca2+ can more easily be removed from binding within the pore due to the presence of an electronegative external vestibule that dehydrates and concentrates permeating ions. Alterations in Ca2+ binding may underlie tonotopic and Ca2+-dependent variations in channel conductance. This Ca2+-dependent rectification provides targets for identifying the molecular components of the MET channel.

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Synková, Jana. „Possibility of utilization of direction construction in river revitalization“. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 57, Nr. 5 (2009): 279–84. http://dx.doi.org/10.11118/actaun200957050279.

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Directing and concentrating structures are used mainly on water coursers with unstable channel and major sediment transport or in areas with major bank erosion. The main purpose of these structures is to redirect water flow from the stressed and very often eroded bank to the centre of the channel or other parts of the channel, where the water flow may be used e.g. for dispersion of unsuitable deposit before its eventual stabilization by natural succession.Another important goal is to achieve a desired change of the stream channel by using the transporting power of the water flow and targeted depositing of sediment. In the area of the deflecting structure (deflector), so-called hydraulic shadow also appears where sediment deposits. The objective is to achieve depositing of sediments at desired places of the stream.It is possible to design a whole range of suitable or less suitable types of flow deflectors. In our article, we will particularly focus on problems of revitalization of a water course; that is design of structures from biological or biotechnical elements for channel stabilization.

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Ma, Zhi Yong. „Research on Concept System of Rotation-Mirror Symmetry in Mechanical Systems“. Applied Mechanics and Materials 201-202 (Oktober 2012): 7–10. http://dx.doi.org/10.4028/www.scientific.net/amm.201-202.7.

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Mechanical rotation-mirror symmetry is grouped by rotation symmetry and mirror symmetry, and belongs to mechanical static structure symmetry. Collecting and Analyzing a lot of rotation-mirror symmetric instances, and referring to the researches on concept systems of rotation symmetry and mirror symmetry, the concept system of rotation-mirror symmetry was established. The concept system is classified by discrete mirror and continuous mirror rotation-mirror symmetry, unidirectional rotation and bidirectional rotation rotation-mirror symmetry, directed rotation and deflecting rotation rotation-mirror symmetry, entire rotation and partial rotation rotation-mirror symmetry. The concept system can completely contain all kinds of existence of rotation-mirror symmetry in mechanical systems.

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Marx, D., R. Assmann, P. Craievich, U. Dorda, A. Grudiev und B. Marchetti. „Reconstruction of the 3D charge distribution of an electron bunch using a novel variable-polarization transverse deflecting structure (TDS)“. Journal of Physics: Conference Series 874 (Juli 2017): 012077. http://dx.doi.org/10.1088/1742-6596/874/1/012077.

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Šlezingr, M., J. Synková, L. Foltýnová und H. Uhmannová. „Possibility of utilization directing structures in river revitalization“. Slovak Journal of Civil Engineering 18, Nr. 3 (01.09.2010): 33–36. http://dx.doi.org/10.2478/v10189-010-0015-3.

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Possibility of utilization directing structures in river revitalizationDirecting and concentrating structures are mainly used on water courses with unstable channels and major sediment transport or in areas with major bank erosion. The main purpose of these structures is to redirect water flow from the stressed and very often eroded bank to the centre of the channel or other parts of the channel, where the water flow may be used, e.g., for dispersion of unsuitable deposits before its eventual stabilization by natural succession. Another important goal is to achieve a desired change in a stream channel by using the transporting power of the water flow and targeted deposition of any sediment. The area of a deflecting structure, a so-called hydraulic shadow, also appears where sediment is deposited (deflector). The objective is to achieve the deposition of sediments at desired places in the stream. It is possible to design a whole range of suitable or less suitable types of flow deflectors. In our article, we will particularly focus on problems of revitalizing a water course; i.e., the design of structures from biological or biotechnical elements for channel stabilization.

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Volkov, V. V., und Y. Zhu. „Magnetic Deflecting Microscopy: A Novel Visualizing Method of Magnetic Stray Fields for Thick or Non-Transparent Magnetic TEM Samples“. Microscopy and Microanalysis 4, S2 (Juli 1998): 404–5. http://dx.doi.org/10.1017/s1431927600022145.

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For microstructure analysis of magnetic materials, in particular, for a new class of Nd-Fe-B hard magnets, a number of magnetic imaging techniques can be applied to gain different microstructure information. For instance, SEM magnetic imaging can be successfully used for very thick samples from a bulk ones down to a sample thickness of 10-20 μ. Below this limit the resolution of SEM magnetic images generally is too low to visualize fine details of magnetic structure. For very thin samples (less then 0.5 μm) magnetic Lorentz microscopy methods in conventional TEM are very useful tools to reveal magnetic domains and their structure. Therefore, it seems that relatively thick films of 0.5-20 μm in thickness are left out of the experimental limits of the methods discussed.We report on a novel, indirect TEM method that allows us to extend the limits of magnetic imaging for TEM non-transparent magnetic samples by viewing the surface stray fields and fringing fields generated by magnetic domains at specimen edge.

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Kania, Tomasz, Valery Derkach und Rafał Nowak. „Testing Crack Resistance of Non-Load-Bearing Ceramic Walls with Door Openings“. Materials 14, Nr. 6 (12.03.2021): 1379. http://dx.doi.org/10.3390/ma14061379.

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Cracking in non-load-bearing internal partition walls is a serious problem that frequently occurs in new buildings within the short term after putting them into service or even before completion of construction. Sometimes, it is so considerable that it cannot be accepted by the occupiers. The article presents tests of cracking in ceramic walls with a door opening connected in a rigid and flexible way along vertical edges. The first analyzes were conducted using the finite element method (FEM), and afterward, the measurements of deformations and stresses in walls on deflecting floors were performed on a full scale in the actual building structure. The measurements enabled to determine floor deformations leading to cracking of walls and to establish a dependency between the values of tensile stresses within the area of the door opening corners and their location along the length of walls and type of vertical connection with the structure.

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Marx, Daniel, Ralph Assmann, Paolo Craievich, Ulrich Dorda, Alexej Grudiev und Barbara Marchetti. „Longitudinal phase space reconstruction simulation studies using a novel X-band transverse deflecting structure at the SINBAD facility at DESY“. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 909 (November 2018): 374–78. http://dx.doi.org/10.1016/j.nima.2018.02.037.

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Chernyavsky, D. I., und D. D. Chernyavsky. „Calculation strength of torsion bar suspension of micromirrors (MEOMS)“. Omsk Scientific Bulletin, Nr. 177 (2021): 5–12. http://dx.doi.org/10.25206/1813-8225-2021-177-5-12.

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The paper considers the strength calculation of the torsion bar suspension of a micromirror with a reflective layer of high optical quality of the surface for deflecting the reflected laser beam. By changing the angle of inclination of the micromirror, the laser beam enters the various input channels of the optical sensor. In this case, a control signal is generated for the further operation of the microcircuit. Thus, the micromirror performs the function of a switch for input optical channels connecting certain input or output elements of the microcircuit in various combinations for further processing. In this work, the calculation of the strength parameters of the mechanical structure of a micromirror made of various materials has been carried out. Practical recommendations related to the development of micromirror torsion bar suspension are given

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Yu, Jiangtao, und Junhong Ye. „Nacre inspired 3D printing construction for high performance structural member“. MATEC Web of Conferences 275 (2019): 02005. http://dx.doi.org/10.1051/matecconf/201927502005.

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Inspired by the nacre’s hierarchically assembled structure, the authors tried to use ultra-high ductile cementitious composites (UHDCC) and stack approach to fabricate structure possessing high flexural ductility and load bearing capacity. A series of beams with specially design was constructed, i.e., monolithically cast beams, monolithically stacked beams and hierarchically stacked beams. Four-point bending tests were carried out to explore the effect of hierarchical assembly on load bearing capacity, flexural deformation and flexural toughness. The test results have indicated that the monolithically stacked beams outperform the monolithically cast beams in both deformability and loading bearing capacity, indicating the effectiveness of stack-based construction. Moreover, the setup of connect/separation between layers further improves the flexural ductility of the hierarchically stacked beams, as compared with the monolithically stacked beams. Digital Image Correlation (DIC) observations indicate that the nacreous-like structure of the hierarchically stacked beam helps to trigger crack deflecting and branching between layers and inside matrix, lead to limited slide between layers, thus effectively relieving concentrated strain inside matrix, postponing the emergence of the critical crack and consequently improving the flexural ductility of nacreous-like UHDCC beams.

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Chen, Ming Wei, Hai Peng Qiu und Wei Jie Xie. „Preparation and Properties of SiC/Si-B-C-N Ceramic Composites“. Key Engineering Materials 697 (Juli 2016): 489–93. http://dx.doi.org/10.4028/www.scientific.net/kem.697.489.

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Abstract：SiC/Si-B-C-N and SiC/SiC ceramic matrix composites were prepared through a combination of chemical vapor infiltration (CVI) and polymer impregnation pyrolysis process(PIP). The microscopic morphology and solid phase structure of the SiC/Si-B-C-N and SiC/SiC composites were investigated by SEM and XRD respectively. Moreover,the flexural strength and fracture toughness were measured using three point bending and single-edge notched beam test. Results showed that the formation of crystalline phases transformation was restrained by introduce BN into matrix phase, which might improve the stability of ceramic matrix composites. Furthermore, the flexural strength and fracture toughness of ceramic matrix composites increased to a maximum of 367 MPa and 26.81 MPa·m1/2 with the 30% PBN weight ratios which might be mainly caused by crack arresting, crack deflecting, micro cracks and fiber pullout.

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Simon, Monique Nouailhetas, Fabio Andrade Machado und Gabriel Marroig. „High evolutionary constraints limited adaptive responses to past climate changes in toad skulls“. Proceedings of the Royal Society B: Biological Sciences 283, Nr. 1841 (26.10.2016): 20161783. http://dx.doi.org/10.1098/rspb.2016.1783.

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Interactions among traits that build a complex structure may be represented as genetic covariation and correlation. Genetic correlations may act as constraints, deflecting the evolutionary response from the direction of natural selection. We investigated the relative importance of drift, selection, and constraints in driving skull divergence in a group of related toad species. The distributional range of these species encompasses very distinct habitats with important climatic differences and the species are primarily distinguished by differences in their skulls. Some parts of the toad skull, such as the snout, may have functional relevance in reproductive ecology, detecting water cues. Thus, we hypothesized that the species skull divergence was driven by natural selection associated with climatic variation. However, given that all species present high correlations among skull traits, our second prediction was of high constraints deflecting the response to selection. We first extracted the main morphological direction that is expected to be subjected to selection by using within- and between-species covariance matrices. We then used evolutionary regressions to investigate whether divergence along this direction is explained by climatic variation between species. We also used quantitative genetics models to test for a role of random drift versus natural selection in skull divergence and to reconstruct selection gradients along species phylogeny. Climatic variables explained high proportions of between-species variation in the most selected axis. However, most evolutionary responses were not in the direction of selection, but aligned with the direction of allometric size, the dimension of highest phenotypic variance in the ancestral population. We conclude that toad species have responded to selection related to climate in their skulls, yet high evolutionary constraints dominated species divergence and may limit species responses to future climate change.

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Mayboroda, Oleksandr. „„Regime-order” and „regime-structure” in political system“. Political Studies, Nr. 1 (2021): 52–69. http://dx.doi.org/10.53317/2786-4774-2021-1-4.

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The article deals with the problem of identification of political system typology in dependence on its mode of operation. The author is of the opinion that political regime is not identical to political system, being a compound of modes and methods of political rule, and according to their nature, the political system is assessed in its working condition. Another thesis propounded by the author is that political regime should be examined both as an „order” of political system operation and as a separate subject with its own system relations among actors realizing political rule. Based on this premise, the notions of „regime-order” and „regime-structure” have been proposed. In effect, it is actually „regime-structure” that regulates the functioning of political system’s „regime-order”, i.e., that determines the character of political rule. Connected to the operation of political system in practice, the notion of „deviation” is introduced in a sense of deflecting a „working” system’s regime from the „project” one, as drawn in constitution and laws. But situations can occur when the system begins to operate in the „working” regime before the „project” regime is established. In such a case, the character of the political „regime-order” becomes dependent on personal moral and political cultural preferences of those who gathered together in „regime-structure”, and their preferences in a form of principles and modes of rule may become the political tradition, at least for some time. The conceptual innovations proposed by the author are illustrated with the account of the evolution of both political regime forms in Ukraine during its political sphere’s independent development. The constant overflowing of ruling modes from one regime to another are caused also by the quality of social environment, first of all due to the domination of paternalist psychology therein. The most negative result of such evolution of feedback between ruling regimes and society is a domination of emotions over rationality in mass political thinking and behavior. Key words: political system, political regime, „regime-order”, „regime-structure”, political rule

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Kayser, R., S. Refsdal, R. Stabell und B. Grieger. „Astrophysical Applications of Gravitational Micro-Lensing“. Symposium - International Astronomical Union 124 (1987): 767–70. http://dx.doi.org/10.1017/s0074180900159893.

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Gravitational micro-lensing due to stars in the deflecting galaxy influences the brightness and the spectra of the macro-images. Thus differences in the spectra of different macro-images are not automatically an argument against gravitational lensing. Furthermore changes in the spectra due to micro-lensing may give informations on the quasar structure. From high amplification events the brightness profile of the source may be obtained. The time scale of the high amplification event is proportional to the source radius and inverse proportional to the transversal velocity. Due to the large brightness gradient by a high amplification event, a “parallax-effect” occurs, from which the transversal velocity may be obtained, and thereby the source radius (R=Δ t · VT). We roughly estimate 0.3 high amplication events per year for all gravitationally lensed quasars. Frequent monitoring should be carried out in order to predict high amplification events as early as possible.

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Nicklin, Chris, Tom Arnold, Jonathan Rawle und Adam Warne. „Diamond beamline I07: a beamline for surface and interface diffraction“. Journal of Synchrotron Radiation 23, Nr. 5 (27.07.2016): 1245–53. http://dx.doi.org/10.1107/s1600577516009875.

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Beamline I07 at Diamond Light Source is dedicated to the study of the structure of surfaces and interfaces for a wide range of sample types, from soft matter to ultrahigh vacuum. The beamline operates in the energy range 8–30 keV and has two endstations. The first houses a 2+3 diffractometer, which acts as a versatile platform for grazing-incidence techniques including surface X-ray diffraction, grazing-incidence small- (and wide-) angle X-ray scattering, X-ray reflectivity and grazing-incidence X-ray diffraction. A method for deflecting the X-rays (a double-crystal deflector) has been designed and incorporated into this endstation, extending the surfaces that can be studied to include structures formed on liquid surfaces or at liquid–liquid interfaces. The second experimental hutch contains a similar diffractometer with a large environmental chamber mounted on it, dedicated toin situultrahigh-vacuum studies. It houses a range of complementary surface science equipment including a scanning tunnelling microscope, low-energy electron diffraction and X-ray photoelectron spectroscopy ensuring that correlations between the different techniques can be performed on the same sample, in the same chamber. This endstation allows accurate determination of well ordered structures, measurement of growth behaviour during molecular beam epitaxy and has also been used to measure coherent X-ray diffraction from nanoparticles during alloying.

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Burkhardt, Anja, Martin Warmer, Nicolas Stuebe, Jan Roever, Bernd Reime, Saravanan Panneerselvam, Tim Pakendorf, Jan Meyer, Pontus Fischer und Alke Meents. „X-ray Crystallography at Beamline P11 at PETRA III“. Acta Crystallographica Section A Foundations and Advances 70, a1 (05.08.2014): C1725. http://dx.doi.org/10.1107/s2053273314082746.

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The bio-imaging and diffraction beamline P11 at PETRA III is dedicated to structure determination of periodic (crystalline) and aperiodic biological samples. The beamline features two experimental endstations: an X-ray microscope and a crystallography experiment. Basis of design was to provide an extremely stable and flexible setup ideally suited for micro and nano beam applications. The X-ray optics consist of a HHL double crystal monochromator, followed by two horizontal deflecting and one vertical deflecting X-ray mirrors. All mirrors are dynamically bendable and used to generate an intermediate focus at 65.5 m from the source with a size of 37 × 221 µm2FWHM (v × h). All experiments are installed on an 8 m long granite support which provides a very stable setup for micro beam experiments. The crystallography endstation is located at the end of the granite at 72.9 m from the source. The experiment is equipped with a high precision single axis goniostat with a combined sphere of confusion of less than 100 nm. X-ray energies are tunable between 5.5 and 30 keV. A second focusing bendable KB mirror system can be used for further demagnification of the secondary source. In this way the beam size can be freely adjusted between 4 × 9 µm2and 300 × 300 µm2FWHM (v × h) with 1013ph/s at 12 keV. Smaller beam sizes down to 1 × 1 µm2with more than 2 × 1011ph/s in the focus can be realized by slitting down the secondary source at the cost of flux. The crystallography endstation is equipped with a Pilatus 6M-F detector which allows fast data collection with up to 25 Hz. Due to the very small beam divergence of the X-ray beam P11 is ideally suited to measure large unit cell systems, such as viruses or large molecular complexes. In addition, the beamline is capable of high-throughput crystallography and fast crystal screening. Crystals can be mounted in less than 10 s using an automatic sample changer. The large sample dewar provides space for 368 crystals.

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Chernyavsky, D. I., und D. D. Chernyavsky. „Kinematic calculation of micro mirror elements in micro electro-mechanical systems (MEMS)“. Omsk Scientific Bulletin, Nr. 175 (2021): 5–11. http://dx.doi.org/10.25206/1813-8225-2021-175-5-11.

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Currently, the development and application of micro machines is an important direction in the development of microelectromechanical systems (MEMS) technologies. In these devices, electromechanical energy conversion occurs, as a result of which forces arise that carry out mechanical work within the dimensions of the microcircuit case. The paper considers the kinematic calculation of the design of a micromirror with a reflective layer of high optical quality of the surface for deflecting the reflected laser beam. By changing the angle of inclination of the micromirror, the laser beam enters the various input channels of the optical sensor. In this case, a control signal is generated for the further operation of the microcircuit. Thus, the micromirror performs the function of a switch of input optical channels, connecting in various combinations certain input or output elements of the microcircuit for further processing. The article presents the calculation of the kinematic parameters of the mechanical structure of the micro mirror. Practical recommendations are given for choosing the optimal range of variation of the micro mirror tilt angles in order to increase the strength of its structure, as well as to reduce the power of the mechanical drive of the micro machine required to change the micro mirror tilt angles

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Wróblewska, Magdalena. „Measurement methods of building structures deflections“. E3S Web of Conferences 36 (2018): 02010. http://dx.doi.org/10.1051/e3sconf/20183602010.

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Underground mining exploitation is leading to the occurrence of deformations manifested by, in particular, sloping terrain. The structures situated on the deforming subsoil are subject to uneven subsidence which is leading in consequence to their deflection. Before a building rectification process takes place by, e.g. uneven raising, the structure's deflection direction and value is determined so that the structure is restored to its vertical position as a result of the undertaken remedial measures. Deflection can be determined by applying classical as well as modern measurement techniques. The article presents examples of measurement methods used considering the measured elements of building structures’ constructions and field measurements. Moreover, for a given example of a mining area, the existing deflections of buildings were compared with mining terrain sloping.

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King, Kim W., Johnny H. Wawclawczyk und Cem Ozbey. „Retrofit strategies to protect structures from blast loadingThis article is one of a selection of papers published in the Special Issue on Blast Engineering.“ Canadian Journal of Civil Engineering 36, Nr. 8 (August 2009): 1345–55. http://dx.doi.org/10.1139/l08-058.

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Structural retrofits to buildings can be implemented to increase the protection level to occupants from potential terrorist bombing attacks. Retrofit strategies discussed in this paper can be categorized into three groups: (i) strengthening concepts, (ii) shielding concepts, and (iii) concepts to control hazardous debris. Strengthening concepts such as span reduction and increasing member sections are considered in this paper for three common construction systems including steel, concrete, and masonry. Shielding concepts are intended to prevent structural members from being fully loaded by blast forces and range from local area applications to entire building coverage. Examples of shielding concepts include a new section of wall that shields a vulnerable portion of the building or a new structure built over an entire building. Examples of concepts to control hazardous debris include arresting or deflecting failed cladding away from critical areas with “catch systems” or internal shield systems. This paper is intended to discuss typical building retrofit strategies for primary structural members (load bearing) and secondary structural members (nonload bearing) through strengthening, shielding, or controlling hazardous debris.

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Lonsdale, Colin J., und Peter D. Barthel. „The Working Surface of a Powerful Radio Source: Global MkIII Observations of the Southern Lobe of 3C205“. Symposium - International Astronomical Union 129 (1988): 135–36. http://dx.doi.org/10.1017/s007418090013428x.

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The radio source 3C205 is identified with a quasar of redshift 1.53, and is, at first glance, a standard, powerful double radio source with hotspots. Upon closer examination (MERLIN, VLA A-array), the southern lobe is seen to consist of two distinct hotspots plus some more diffuse emission, some 50 kiloparsecs from the quasar (Ho ∼ 75). The arcsecond-scale morphology and polarization structure of this hotspot complex strongly suggests that the larger and weaker off-axis secondary hotspot has been formed by outflow of material from the more compact primary hotspot (Lonsdale and Barthel 1984,6). This interpretation implies a collision between the presumed energy supply beam and something capable of deflecting the flow energy towards the secondary. Because the flow is so energetic, this obstacle would have to be both massive and dense. The main constraint on the density of the obstacle comes from measurements of the internal energy density of the compact primary hotspot coupled with model-dependent estimates for the maximum advance velocity of this feature, thus yielding a balance with the ram-pressure exerted by the obstacle medium.

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Sógel, K. „Timber beams subjected to long - term loading“. Slovak Journal of Civil Engineering 18, Nr. 3 (01.09.2010): 21–26. http://dx.doi.org/10.2478/v10189-010-0013-5.

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Timber beams subjected to long - term loadingWood is a significant structural material, which is often used for timber bearing structures. Elements of timber structures must especially satisfy safety requirements, which are expressed by the ultimate limit states in the established standards. The structure must also satisfy the serviceability limit states. Local and global deformations make it impossible for the structure to serve the purpose it was designed for. It is important to take the deflections and their possible increase into account in the design to provide a structure which can be used during the whole period of service. Based on earlier examinations, it is known that a timber element over the course of long-term loading shows creep behavior. The structure of wood is able to adapt to the conditions of the surrounding environment. The properties of wood are especially affected by the relative humidity of the air and then by the type, intensity and duration of the loading. The most important factors affecting the serviceability of timber structures are volume changes caused by humidity and additional deflections caused by the effects of long-term loading. These phenomena emphasize the importance of serviceability limit states for timber structures. The paper deals with a long-term experimental investigation of timber girders that are currently often used. The aim was to obtain the deflection curves and mark the time dependence and the final deflections. The paper will also define the approximations for simulating the time-dependent deflections and obtain the creep coefficients for calculating the final deflections of the girders investigated.

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Zhao, Jing-Shan, Li Ye, Fulei Chu und Jian S. Dai. „Synthesis and static analysis of the deployable frame for a morphing wing“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 227, Nr. 3 (22.10.2012): 565–79. http://dx.doi.org/10.1177/0954406212464728.

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This article proposes a deployable frame for a morphing wing. The frame is redundantly constrained in structure, and therefore it has both merits of high structural stiffness and strength of a truss structure and motion flexibility of a mechanism. The primary element of the foldable frame is synthesized from the viewpoint of identical strength principle. The major structures of previous deployable wings are mostly based on prismatic joints. However, the deflections of the cantilevered links might not satisfy the primary geometry requirements of the prismatic joint. Therefore revolute joints are used in our deployable frame to avoid violating the geometry conditions for prismatic joints resulting from the different deflections of its contacting two parts. The deflection and slope of every joint node of the foldable frame is investigated within the deploying/folding process. Numerical analysis indicates that the deployment ratio of the foldable frame can be designed much larger than that of the existing morphing wing even considering the allowable deflection under the completely unfolded situations.

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Park, Hyo Seon, H. M. Lee, Y. H. Kwon, J. H. Seo und Hong C. Rhim. „Assessment Model for the Safety and Serviceability of Steel Beams Using Terrestrial LiDAR“. Key Engineering Materials 321-323 (Oktober 2006): 248–53. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.248.

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Structural monitoring is concerned with the safety and serviceability of the users of structures, especially for the case of building structures and infrastructures. When considering the safety of a structure, the maximum stress in a member due to live load, earthquake, wind, or other unexpected loadings must be checked not to exceed the stress specified in a code. Although the steel will not fail at yield, excessively large deflections will deteriorate the serviceability of a structure. Therefore, to guarantee the safety and serviceability of steel beams, the maximum stress and deflection in a steel beam must be monitored. However, no practical method has been reported to monitor both the maximum stress and deflection. In this paper, assessment model for both safety and serviceability of a steel beam is proposed. The model was tested in an experiment by comparing stress level estimated by LiDAR system and stress level directly measured from electrical or fiber optic sensors. The maximum deflection measured from LiDAR system is also compared with the maximum deflection directly measured from LVDTs. In addition to displacement measurement, the proposed system can provide information on deformed shapes of steel beams.

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Turner, Dennis J., Jeffrey L. J. Lee, Kenneth H. Stokoe, Richard L. Boudreau, Quintin B. Watkins und George K. Chang. „Discrete and Continuous Deflection Testing of Runways at Hartsfield Atlanta International Airport, Georgia“. Transportation Research Record: Journal of the Transportation Research Board 1860, Nr. 1 (Januar 2003): 76–89. http://dx.doi.org/10.3141/1860-09.

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The measurement of deflection characteristics is a key feature in the evaluation of pavements. Deflections are used to evaluate pavement moduli, relative stiffness, load transfer, and, when used periodically, a rate of deterioration and remaining life. The comprehensive deflection testing program conducted on Runways 9L/27R and 8R/26L, both jointed concrete pavements, at the Hartsfield Atlanta International Airport is described. A heavy-weight deflectometer was used to measure deflections at discrete locations on slab interiors, transverse joints, longitudinal joints, and slab corners. A rolling dynamic deflectometer was used to measure continuous deflection profiles along three longitudinal lines on both runways. Before fall 2001, all pavement deflection testing was performed using a falling-weight deflectometer. Comparisons of the equipment, loading mechanisms, and measured deflections are presented.

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Zihan, Zia U. A., Mostafa A. Elseifi, Patrick Icenogle, Kevin Gaspard und Zhongjie Zhang. „Mechanistic-Based Approach to Utilize Traffic Speed Deflectometer Measurements in Backcalculation Analysis“. Transportation Research Record: Journal of the Transportation Research Board 2674, Nr. 5 (16.04.2020): 208–22. http://dx.doi.org/10.1177/0361198120914296.

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Backcalculation analysis of pavement layer moduli is typically conducted based on falling weight deflectometer (FWD) deflection measurements; however, the stationary nature of the FWD requires lane closure and traffic control. In recent years, traffic speed deflection devices such as the traffic speed deflectometer (TSD), which can continuously measure pavement surface deflections at traffic speed, have been introduced. In this study, a mechanistic-based approach was developed to convert TSD deflection measurements into the equivalent FWD deflections. The proposed approach uses 3D-Move software to calculate the theoretical deflection bowls corresponding to FWD and TSD loading configurations. Since 3D-Move requires the definition of the constitutive behaviors of the pavement layers, cores were extracted from 13 sections in Louisiana and were tested in the laboratory to estimate the dynamic complex modulus of asphalt concrete. The 3D-Move generated deflection bowls were validated with field TSD and FWD data with acceptable accuracy. A parametric study was then conducted using the validated 3D-Move model; the parametric study consisted of simulating pavement designs with varying thicknesses and material properties and their corresponding FWD and TSD surface deflections were calculated. The results obtained from the parametric study were then incorporated into a Windows-based software application, which uses artificial neural network as the regression algorithm to convert TSD deflections to their corresponding FWD deflections. This conversion would allow backcalculation of layer moduli using TSD-measured deflections, as equivalent FWD deflections can be used with readily available tools to backcalculate the layer moduli.

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Dewhurst, Peter, und Sriruk Srithongchai. „An Investigaton of Minimum-Weight Dual-Material Symmetrically Loaded Wheels and Torsion Arms“. Journal of Applied Mechanics 72, Nr. 2 (01.03.2005): 196–202. http://dx.doi.org/10.1115/1.1831295.

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A cylindrically symmetric layout of two opposite families of logarithmic spirals is shown to define the layout of minimum-weight, symmetrically loaded wheel structures, where different materials are used for the tension and compression members, respectively; referred to here as dual-material structures. Analytical solutions are obtained for both structure weight and deflection. The symmetric solutions are shown to form the basis for torsion arm structures, which when designed to accept the same total load, have identical weight and are subjected to identical deflections. The theoretical predictions of structure weight, deflection, and support reactions are shown to be in close agreement to the values obtained with truss designs, whose nodes are spaced along the theoretical spiral layout lines. The original Michell solution based on 45 deg equiangular spirals is shown to be in very close agreement with layout solutions designed to be kinematically compatible with the strain field required for an optimal dual-material design.

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Fang, Lijin, und Yan Wang. „Study on the stiffness property of a variable stiffness joint using a leaf spring“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, Nr. 3 (01.03.2018): 1021–31. http://dx.doi.org/10.1177/0954406218761221.

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Variable stiffness joints designed to ensure physical safety or adjust stiffness actively have attracted much attention in recent years. Springs are used in the internal kinematic structures of variable stiffness joints to achieve the compliance. In this paper, the stiffness property of a variable stiffness joint using a leaf spring is studied on the basis of geometric nonlinearity associated with large deflections of leaf springs. A new end structure is used in the variable stiffness joint to exert the external force on the leaf spring. Based on the elliptic integral solution to large deflection problems of cantilever beams, the effects of different end exertion force structures and geometric nonlinearity of leaf springs on the stiffness property are analyzed when the deflected angle of the joint is larger. It is found that the end exertion force structure and large deflection of leaf springs have a great impact on the changes of the joint stiffness during the joint deflection. A new variable stiffness joint using two leaf springs is proposed to meet different application requirements by changing the end exertion force structure. The experiment of the proposed joint is carried out to verify the validity of the stiffness analysis results.

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Šmejkal, Jiří, und Jaroslav Procházka. „Design of Ceiling Structures with Regards to Deflection“. Solid State Phenomena 249 (April 2016): 241–45. http://dx.doi.org/10.4028/www.scientific.net/ssp.249.241.

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The standard EN 1992-1-1 [1] provides two approaches to limiting deflection of ceiling structures. One approach is limitation of bending slenderness using simple formulas. The second approach is the direct calculation of deflection. In the paper, there are analyzed restrictive conditions for the use of limited bending slenderness. Further there are design approaches for determining deflections of conventional floor building structures. Then there is mentioned the solution of estimating of total deflection from the linear FEM calculations. Information on other methods of determining the deflection of ceiling structures is given in the end.

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Evkin, Alexander, Maksym Kolesnikov und Olga Lykhachova. „Buckling load prediction of an externally pressurized thin spherical shell with localized imperfections“. Mathematics and Mechanics of Solids 24, Nr. 3 (29.01.2018): 653–67. http://dx.doi.org/10.1177/1081286517753277.

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A simple formula for buckling load was derived from the asymptotic analysis of nonlinear behavior of a thin spherical shell. Firstly, two asymptotic cases were studied: the initial post-buckling regime of a perfect structure with small (compared to shell thickness) deflections and equilibrium states with large deflections. Two asymptotic formulae were jointed to obtain the solution for the entire range of deflection amplitude. Then the solution was modified for an imperfect shell. Initial deflections were introduced by only one parameter: the slope of the load–deflection diagram at small pressure. This minimal information was enough to predict the buckling load of the structure with localized imperfections. The suggested asymptotic result was validated by the finite element method and by comparison with experimental data.

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